Its not your fault, I know how you feel though, Tonight I went to check on the 5 stray kittens we have by my house and in the corner of this old shed where they and there mom live was 2 baby bunnie cuddled up all scared I wanted to jump in and grab them but I couldnt really get in without the people who own the shed hearing me and seeing me in their shed. I saw rabbit fur in that area also so my guess is the mother cat already got one of the other babies or the momma bunny I just want to cry but I know its nature I will hopefully go check tomorrow morning and if I can get the baby bunnies out maybe I will let them go in my yard somewhere if they are even alive.